The present invention relates generally to wireless metropolitan area network systems and mobile broadband wireless systems, and more particularly to a distribution network for coupling wireless network signals of these systems between centrally located internetworking devices and remotely located access points. Wireless metropolitan area network systems may include systems that are compatible with the Institute of Electrical and Electronic Engineers (IEEE) 802.16 wireless metropolitan area network (MAN) standard. Mobile broadband wireless systems may include systems that are compatible with the IEEE 802.20 mobile broadband wireless network standard.
The most common user applications for personal computers now require a connection to a computer network of some type. Such applications include the viewing of e-mail, sharing of data files, and accessing the Internet and the World Wide Web. Various techniques are used for connecting computers together so that they may send data to and receive data from each other, more or less in real time. Most often this so-called physical layer is implemented using wires and the bits of data to be exchanged are converted into electrical signals that move through the wires. Traditionally, local area networks (LANs) were implemented using privately installed wiring, such as coaxial cable or twisted pair type cable and network adapter circuits. Later, it became possible to construct LANs through the use of the public switched telephone network and modem equipment.
However, networks that use infrared light or radio frequency energy at the physical layer are growing in popularity. For example, wireless metropolitan area networks (“wireless MANs”) and mobile broadband wireless networks (“MBW networks”) convert the bits of data into radio waves to enable their transmission over the air, which in turn minimizes the need for hard wired connections.
Wireless MANs are applicable where user portability over a large coverage area is important, while mobile broadband wireless applies to wireless links to high speed vehicles. In both cases, deployment requires the added cost of the required wireless network adapters and the associated data backhaul networks. These wireless systems will become more widely recognized as a general purpose alternative for a broad range of business applications as the cost of mobile computing equipment such as laptop computers and personal digital assistants (PDAs) continues to decrease. For example, with a wireless MAN, users can access shared information without first stopping to find a place to plug-in their equipment. In addition, network managers can set up or augment such networks without installing or moving wires around from place to place.
A common type of multi-user MAN utilizes multiple devices referred to as access points each collecting signals from multiple portable wireless devices. The access points collect signals transmitted from personal computers equipped with wireless network adapters, and distribute them over wired physical media to other internetworking devices such as repeaters (hubs), bridges, routers, and gateways, to provide interconnectivity to larger networks. Another type of network uses wireless MANs as wireless backhaul for shorter range wireless LANs or other more distant wireless MANs as part of a wireless mesh network.
The range of a wireless MAN or mobile broadband wireless access point is limited by how far the signals can travel over the air between the access points and the network adapters connected to the PCs/PDAs etc. Physical terrain and manmade physical structures further decrease propagation range even though these wireless signals are designed to survive the interference caused by multipath reflections and scattering.
To extend coverage beyond this limited range, a network of access points with overlapping radio ranges must be located throughout the desired coverage area. These so-called infrastructure wireless MANs and mobile broadband wireless networks are implemented in a manner which is similar to a cellular telephone system. At any given time, a mobile personal computer equipped with a wireless adapter communicates with at least one access point within its receiving range. On the landline side, the access points are interconnected using network-compatible twisted pair wiring such as that which is compliant with the Ethernet/802.3 10baseT or 100baseT standard. The network signals can then be further forwarded to a local- or wide-area network using standard internetworking protocols and devices.